Telephone-exchange system



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Dec. 29 1925- L. KELLER ET AL TELEPHONE EXCHANGE SYSTEM Filed March 311923 15 Sheets-Sheet 15 xkkim QEQ QQ QQ Patented Dec. 29, W25.

. UNETED STATES PATENT OFFICE.

LEO KELLER, OF NEW YGRK, AIID SAMUEL B. NILLLAMS, OF BROOKLYN, NEW YORK,ASSIGNORS TO "WESTERN ELECTRIC COMPANY, INGORPORATED, OF NEW YORK,

N. Y., A CORPORATIQN OF NEW' YORK.

TELEPHONE-EXCHANGE SYSTEM.

Application filed March 31, 1923. Serial No. 628,988.

To all whom it concern.

Be it known that we, Leo KELLER and SAMUEL B. Wrnnnmrs, citizens of theUnited States, residing at New York, in the county of New York, andBrooklyn, in county of Kings, respectively, and State of New York, haveinvented certain new and useful Iniproveine'nts in Telephone-ExchangeSystems, of which the following is a full, clear, concise, and exactdescription.

This invention relates, in general, to telephone exchange systems andmore specially to systems employing machine switching apparatus for theestablishment of conversational connections.

The object of the invention is an improved arrangement for distributingor apportioning the traffic to the switching apparatus of the exchange.

A feature relates to the provision, in a system where the switches aredivided into groups with a controlling mechanism allotted to each group,of means for diverting the tratfic normally incoming to a given group ofswitches to other switches when trouble occurs in the correspondingcontrolling mechanism.

Another feature relates to the provision of an arrangement whereby thecontrolling mechanism allotted to a group of switches alters the controlof such switches to divert calls to an operators position which normallywould be directed into a succeeding group, providing trouble exists inthe equipment of such succeeding group.

Other and further advantages of this invention will be pointed out indetail in the description hereinafter and also in the appended claims.

Considering the drawing, Figs. 1 to 14, inclusive, when arranged in theorder illustrated in the diagram of Fig. 16 disclose the details of atelephone system incorporating the features of the present invention.

Fig. 1 illustrates a line SWltlll 9f the co ordir to type in which thesubscribers lines terminate. and also two of av number of trunksoutgoing to a district selector switch. 7

F 2 shows certain control elements associated with the outgoing trunkand also illustrate. a t ouble operator s position.

3 disc. H esp district Selector switch of the coordinate type in whichterminate the trunks incoming from the line switches.

Fig. 4: illustrates a coordinate group selector switch in whichterminate the trunks incoming from the district selectors.

Fig. 5 shows a coordinate connector switch for completing connections tothe subscribers lines.

Fig. 6 represents a sender selector switch also of the coordinate type.

Figs. 7, 5 and 9 depict one of a number of register senders.

Fig. 10 shows a sender connector device for connecting any of theplurality of senders with the common marker or selection controllingdevice.

Figs. 11 and 12 illustrate the marker con trolling device.

Fig. 13 shows a sender connector device for connecting the line markerwith any of the several register senders. This figure also shows thetesting relays for testing the condition of the trunks incoming to thegroup selector and connector switches together with certain controlelements of the line marker.

Fig. 14 discloses the remainder of the line marker.

Fig. 15 is the schematic showing of a telephone system employingswitches and controlling apparatus of the type shown in detail in theother figures.

Referring to Fig. 15, the subscribers lines entering the exchange appearas calling lines in a number of coordinate line switches 1500, 1501 and1502. The rectangle 1500, for example, may represent a plurality ofswitches which receive a given group of calling lines. Likewise,rectangles 1501 and 1502 represent other switches receiving other groupsof calling lines. The trunks outgoing from the switches 1500 aredistributed in any suitable manner among a plurality of groups ordivisions, each division consisting of a plurality of district or firstgroup selector switches.

The rectangles 1503, 1504 and 1505 each represent a plurality ofdistrict selectors which all taken together comprisethe first group ordivision of switching equipment. Certain of the trunks outgoing from theline switches 1500 15.0], 1502 are directed into the district switchesof this first division. Similarly, other trunks outgoing from the lineswitches are distributed among the district selectors of a second groupor division comprising district selectors 1506, 1507 and "1508.Likewise, as many other divisions distributed that any of the districtselectors may obtain access to any of the. different terminal linegroups.

The first division of switches is provided with a plurality of registersenders 1514., 1515, etc., a. single district marker 1516 and therequisite number of sender selector switches 1513. The sender selectors1513 serve to pick out an idle one of the register senders and associateit with the trunks extending from the line switches'to the districtselectors of the first division. The senders are all associable with thedistrict ina'rker 1516, which in turn, may be assoc ated with any one ofthe district switches in the first division in order to control thesetting movement of such switch. Likewise, the second divisionisprovided with similar equipment consisting of sender selectors 1517,senders 1518, 1519, etc. and district marker 1520.

The terminal line groups are provided with individual line markers 1521and .1522 which are associable with any register sender pertaining toany division and which control the group selector and connector switcheso'fthat particular group to complete the connection throughto a calledline.

Should it be discovered that the district marker 1516 pertaining to thefirst division is in trouble or should for any reason itbe desirable'toprevent calls coming into the district selectors of such division. thetrouble operator throws a key 1526. This key serves to render all trunkswhich lead into the district switches 1503, 150 1 and 1505 of the firstdivision non-selectable to the line switches. This means that-the traficincoming to the line switches will now be forced to find its way overtrunks outgoing from the line switches into the district switches ofother divisions. In a similar manner should trouble exist in the second,or any of the otherdivisions, the operator-by throwing a key similar tothe key 1526 would divert trathc from such CllVlSlOD. Again should.

General description of the system and apparatus.

The line switch 100, selector switches 300 and 400, connector switch 500and the sender selector switch 600 employed in this system are of thecoordinate type such as shown and described in the British Patent183,436, ac-

cepted August 23, 1923, granted to the lVestern Electric Company,Limited, and in the patent to S. B. Williams, No. 1,517,331, grantedDecember 2, 192 1. 7

The subscribers lines enter the exchange and appear inthe coordinateline switches in vertical rows and 111, each line having access to agroup of horizontal links such as the groups represented by links 106,

107, and links 108, 109. Line 101, for instance, has access to the groupof links containing the links 106 and 107. Each of the outgoing trunks11.4: and 1.15 occupies a full vertical row of contacts 112, 113 andleads to the district switches.

The trunk 114; which is shown in full appears in the district switch 300occupying the vertical row of Contacts 308. Another trunk115=outgoingfro1n the line switch 100 is shown occupying the fullvertical row of contacts 309. District selector switch 300 also has aplurality of groups of outgoing trunks appearlng 1n the rows 311, 312,313,

'etc. 7 Each outgoing trunk is snown having an appearance before asingle one of the horizontal links 331, 332, 333, etc. These trunks aremultipled as explained to appear before corresponding horizontal linksin all other district selectors of the same division.

Since the subscribers lines are divided into a number of groups ofcalled lines, known as terminal line groups, the trunks outgoing fromthe district switches are arranged in corresponding groups so that thedistrict switches have access to any of the terminal line groups. of theswitching appa -atus. The group of trunks appearing in the upper section302 of the vertical row 311 inthe district switch 300 lead to the groupselector switches of a particular terminal line group. One of thesetrunks is shown leading to the group selector switch 400. The group oitrunks occupying the lower section of the same vertical row may run tothe group selectors of the same or of a. different terminal line group,as desired. Other groups outgoing from the district switches aredistributed to other terminal line groups of switching apparatus. Inaddition to these groups of trunks leading-s to the terminal linegroups, the district switches may be provided with trunks extending inother directions. For instance, the group of trunks appearing in thesection 301 of the vertical row 314E lead to an answering operatorsposition 330.

The groups of trunks outgoing from the group selector 400 and from othergroup selectors in the same terminal group are distributed to a suitablenumberof connector switches. One or" these connectors 500 shown and asin le trunk incomin from the selector switch 100.

The called subscribers lines appear in the connector switches in groups.For example, the'vertical rows 52 1, 525, each represents a group ofsubscribers lines. Each line is ac veessible over a group 01' horizontallinks.

The line 516 appears in the group occupying the vertical row 525 and isaccessible by a groupot' links, two of which, 501 and 502,

are shown. A second line 526 appearing in the same group 1s accessibleby another group of horizontal links 504, 505.

The district marker shown in Figs. 10, 11 and 12 includes two registers1101 and 1102 .which receive their registration from the controllingsenoer. These registers determine the setting of a multicontact relaytranslating device 1100 wluchresults in the I selection of one of anumber of group relays 1230, 1231, 1232. These latter relays determinethe setection ot' a group of trunks at the district switches.Furthermore, the translator comprises two sets of testing relays 1200and 1203. The set 1200 serves to test the horizontal links of thesection 302 in any district selector switch of this division and also totest the outgoing trunks which have access to these horizontal links.Connecting device 1202 which comprises a number of multicontact relays1215, 1210. etc. serves to connect the set of relays 1200 with theproper group of outgoing trunks. Likewise. the other set of test relays1203 serves of outgoing trunks.

with respect to the set of horizontal links 301 all switches and theoutgoing trunks to The connect ing device 1201 consisting of a number ofrelays 1212. 1213. etc, acts to associate the testing relays 1208 withthe proper groups Also a connecting de' vice 1201. consisting ofInulticontact relays 1222, 1223, 219. 1220, 1225 and 1226 serve toconnect the marker testing relays with the individual switches of thedivision.

The line marker shown in Figs. 13 and 14. includes a plurality ofregisters 1 100. 1 101 and 14.1 )2 which receive the nun ierical recordfrom the controlling sender. It also includes a inulticontact relaytranslating device 140-1- which is operated according to the settings ofthe registers to select the magnet 511. individual to the dilicrentvertical rows of outgoing lines in the connector switches. It oreovei'.the marker includes a multicontact relay device l i-03 which serves toassociate the register 1 101 with a connecting device 510 individual tothe proper connector switch 500. The device 510. consisting of relays511, 512. etc., serves to associate certain test relays with thehorizontal links of. the group having access to the called lines oi thedesired units designation. In Fig. 13 the set oi testing relays ot themarker are associable through the niulticontact relay connecting devices401 and 402 with the groups of trunks outgoing filOIl'l the selectorswitch and other switches and with the horizontal links 01? these groupselectors.

Detailed description of establishment of (6 connection.

Consider that the subscriber of line 101 d sires to hold conversationwith the subsc iber at line 510 appearing in the same central oii' ce.It may also be assumed that the directory number of line 516 is A B 1 23 -11. lVhen the subscriber of line 101 takes down his receiver acircuit is closed from battery through the winding of line relay 121.inner contact of cut ofli relay 120. coiuluctor 10-1. through thesubstation and returning over condiuaor 10 3 to ground at the outercontact of relay 120. .lclav 121 operates and a circuit is closed frombattery through the winding o't relay 129. right back contact of relay128. left contact of relay 12]. conductor 150 to ground.

Relays 128, 129 and 130 enclosed within the broken rectangle pertain tothe vertical group of lines appearing in the row o't' the switch 100.These relays are brought into action whenever one of the lines in thecm'responding group initiates a call.

Relay completes a circuit from battery through the winding of relay 131.inner front contact of relay 129 to ground. Relay 129 also closes acircuit troni battery through the left-hand winding of relay 130. outerfront contact of relay 129. left back contact of relay 135. outer rightcontact of relay 137, conductor 158 to ground. Rel-av 130 operates andcloses a circuit For relav 12S. Relay 128 looks through its left contactand the left contacts of relays 131 and 132 to ground. Relay 130, inoperating, completes a circuit;- troni battery through its right-handwinding and inner right contact, winding of relay 135. outer rightcontact of relay 137. conductor 158 to ground. Relay 135 operates andcloses a circuit from battery through the winding ot slow-to-releaserelay 130. inner contact of relay 137, conductor 158 to ground. Relay136 closes a substitute holding circuit for relays 130 and 135independent of the relay 137.

WVith relay 135 operated a circuit is closed from battery through thewinding of the vertical magnet 116, outer right front contact of relay130, left front contact of relay 135, contact of relay 136, conductor158 to ground. The magnet 116 operates and prepares the contacts in thevertical row 110. Magnet through its contact, conductor 159, innercontact of relay 134, outer left contact of relay 130, right contact ofrelay 121, left-hand winding of relay 122 to battery. The relay 122 is agroup relay individual to the group of horizontal links including thelinks 106 and 107. Similarly, relay 123 is a group relay individual tothe group containing the links 103 and 109. Relay 122 operates andcloses a circuit from battery through its right-hand winding and rightfront contact, right back contact of relay 123 (assuming this relay tobe deenergized), winding of relay 134, conductor 159 to ground at thecontact of magnet 116. Relay 134 also operates in this circuit.

Another circuit is closed from battery through the winding of thevertical operating magnet 118, brush 144 of allotter switch 143, contactof slow-to-release relay 139, left contact of relay 137, outer rightcontact of relay 135, conductor 158 to ground. It is assumed that thefirst one of the outgoing trunks 114 is idle at the time this call ismade and that the allotter switch 143 is standing in a position to allotthis trunk as shown in the drawing. The allotter switch 143 has aposition for each of the several trunks which lead out of the lineswitch 100 to the succeeding district selectors. Consequently thevertical magnet 118 relative to the idle trunk 114 operates and preparesthe contacts ofthe vertical row 112. Magnet 118, in operating, completesa circuit from battery through its winding and inner contact, conductor160, winding of relay 137;

outer right contact of relay 135 to ground. Relay 137, however, beingshunted by the circuit above traced does not operate at this time.Magnet 1.18. furthermore, closes a circuit from ground through its outercon tact, conductor 151. winding of the trunk relay 146 to battery.

\Vith relay 146 operated a circuit is completed from battery through thewinding of relay139, winding and contact of stepping magnet 138, brush145, contact of relay 146 to ground over conductor 151. The step pingmagnet 138 operates, interrupts its own circuit and advances the brushes144, 145 and 154 to the next set of terminals. If the following trunk isidle the allotter switch comes to rest, but if it is busy the switch 116also closes a circuit from ground, I

continues until an idle trunk is found. When the switch leaves theposition shown, it opens the shunt around the Winding of relay 137 andthis relay operates in series with the magnet 118. Relay 137 opens the.

operating magnet 125 to battery. Magnet 125 operates and effects aconnection between the link 107 and the incoming line and also betweenthe link and the outgoing trunk 114. Immediately that this connection isestablished a circuit is closed from battery through the winding ofmagnet 125, winding of relay 127, contacts of the switch 100, over thesleeve conductor to ground at the outer contact of magnet 118. Theswitch is temporarily held by means of this circuit. The relay 127however, being shunted, does not operate at this time. Another circuitis closed from battery through the winding of cut-off relay 120,conductor 105, through contacts of the switch, over the sleeve conductorto round at the contact of magnet 118. Relay 120 opens the circuit ofrelay 121, which in turn, opens the original energizing circuit of relay129.

Should another line in the same vertical group attempt simultaneously tomake a call while a subscriber in a succeeding vertical 1 group iscalling, his attempt to make such a call will be unsuccessful. When theline relay 121 releases it opens the holding circuit of relay 131, butsince a second subscriber of the same group is calling, relay 131 isheld energized over a parallel circuit through the left contact of theline relay similar to relay 121. Relay 131 in remain ing energizedpreserves the locking circuit of relay 128, which prevents thereenergization of relay 129. A second subscriber in the first group,therefore, cannot succeed in making a call until all simultaneous callsin subsequent groups have been handled or until a call has been made ineach one of said succeeding groups. In this latter event a seriescircuit is closed for relay 132 through and relay 127 is energized whenmagnet 118 ing of relay 613 to battery. Relay 613 operates and locksthrough its winding and inner left contact, conductor 207 to ground atthe outer left contact of relay 201. Relay 613 completes a circuit fromground through its outer right contact, conductor 209, winding ofslow-to-release relay 204 to battery. Relay 204 operates and appliesholding ground to the conductor 150, whereby magnet 125 and relays 120and 146 are held energized becomes deenergized. Relay 613 operatessimilarly to the relay 120 of the line switch and brings the grouprelays 614, 615 and 616 and the control relays 619, 620, 621, 617, 622

' and 623 into play to bring about the extension of a connection throughthe sender selector switch 600 to the allotted idle register sender.

With relays 616 and 617 operated a circuit is closed from batterythrough the winding of the vertical magnet 635, contacts of relays 616and 617, contact of relay 622, conductor636 to ground. Magnet 635operates and brings about the energization of relay 612, which in turn,locks in a circuit including the relay 621. Relay 617 also closes acircuit from battery through the winding of vertical magnet 631, brush627 of allotter 626, contact of slow relay 625, left contact of relay623, outer right contact of relay 617 to ground over conductor 636. Themagnet 631 operates and closes a locking circuit through its windl ingand contact and the winding of relay 623, the latter relay, however,remaining deenergized due to the shunt around its winding. Magnet 631also closes a circuit from ground through its outer contact, conductor638, through the brush 628, contact and winding of magnet 624, windingof relay 625 to battery and ground. Magnet 624 steps the switch 626forward to the set of terminals representing the next idle sender and ina so doing removes the shunt around the winding of relay 623. Relay 623opens the circuit of slow relay 622 which commences to release.

During the interval relay 622 is deenergizing a circuit is closed fromground over conductor 636, inner right front contact of relay 623, rightcontact of relay 621, left front contact of relay 612, front contact ofrelay 611, assuming the link 608 to be busy, back contact of relay 609,winding of the horizontal magnet 610 to battery. Magnet 610 operates theswitch and connects the incoming trunk conductors through the link 607to the group of conductors 632 leading to the selected idle sender.Immediately that the connection is established a circuit is closed frombattery through the winding of relay 201, conductor 210, throughcontacts of the switch, conductor 638 to ground at the contact of themagnet 631.

Relay 201 operates and opens the circuit of relay 613 which causes thedeenergization of relays 612 and 619, provided no other sender is beingsought through the same vertical group. Relay 201 also closes a holdingcircuit for the relay 204 which maintalns a holding ground on theconductor 150. Furthermore, relay 201 connects the tip and ringconductors of the trunk through the sender selector switch to theimpulse relay 7 00 of the sender. This results in the closure of acircuit from battery through the resistance 718, winding of relay 700,outer left contact of relay 703, conductor 640, through the senderselector 600 to conductor 641, outer right contact of relay 201,conductor 149, thence through the line switch 100 and the subscriberssubstation and returning over the other side of the line to conductor148, to the inner right contact of relay 201, conductor 642, through thesender selector 600, conductor 643, inner left contact of relay 703,righthand winding of the balancing coil 701 to ground. Relay 700operates and closes a circuit for the slow-to-release relay 702. Relay702 places ground on the holding conductor 720. This ground potential istransmitted by way of conductor 638 and results in a holding circuit forthe magnet 610 and relays 609 and 201 in substitution of the circuittemporarily maintained by the vertical operating magnet 631.

Following the series of operations just related, slow relays 136 and 622become deenergized. Relay 136 opens the circuits of re lays 130 and 135.Relay 130 opens the circuit of vertical magnet 116 and relay 135 opensthe holding circuit of magnet 118 and relay 137. Magnet 116 causes therelease of relays 134 and 122. Relay 122 removes the shunt and letsrelay 127 operate. \Vith the magnets deenergized the connection is nowheld through the line switch 100 due to the maintained energization ofthe magnet 125 which as above mentioned is held in a circuit closed toground over the sleeve conductor 150.

Relay 622 in releasing similarly brings about a release of correspondingelements in the sender selector switch 600 and the connection throughthe sender selector is held by the magnet 610, the circuit of which iscontrolled by the slow relay 702 in the sender.

The apparatus is now in condition for receiving the first series ofimpulses. It will be recalled that the designation of the wanted line isA B 1 2 3 4. The letters A and B are abbreviations of the exchange nameand represent two series of impulses which precede the numericalimpulses. The letter A may represent two impulses and the letter 13three impulses. The calling subscriber, consequently, manipulates hisimpulse transmitter 163 to send a series of two impulses.

At the time relay T02 operates it closes

